Method and apparatus for estimating line inductance for PWM rectifier control

Abstract

A rectifier includes a switching circuit and a controller. The switching circuit is coupled between positive and negative buses and a plurality of input voltage sources. The switching circuit includes a plurality of pairs of switching devices. Each pair is associated with one of the input voltage sources. The controller includes first and second control loops operable to generate control signals for operating the pairs of switching devices to generate a potential across the positive and negative buses. The controller is further operable to estimate a line inductance seen by the rectifier based on at least one of the control signals and generate an inductance compensation gain factor for applying to the control loops based on the estimated line inductance.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]Not applicable.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not applicableBACKGROUND OF THE INVENTION[0003]The present invention relates generally to power conversion and conditioning and, more particularly, to estimating line inductance for controlling a pulse width modulation (PWM) rectifier.[0004]This section of this document is intended to introduce various aspects of art that may be related to various aspects of the present invention described and / or claimed below. This section provides background information to facilitate a better understanding of the various aspects of the present invention. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.[0005]Power plants are linked to power consuming facilities (e.g., buildings, factories, etc.) via utility grids designed so as to be extremely efficient in delivering massive amou...

AI Technical Summary

Benefits of technology

The present invention relates to a rectifier with a switching circuit and a controller. The controller generates control signals to operate the switching devices and estimate the line inductance based on the control signals. An inductance compensation gain factor is generated based on the estimated line inductance to improve the control of the rectifier. The technical effect of the invention is to improve the efficiency and accuracy of the rectifier control.

Problems solved by technology

Diode rectifiers typically encounter difficulty in attempting to met the harmonic distortion constraints.

Typical PWM rectifiers are better able to meet the harmonic distortion requirements, but are more costly than conventional diode rectifiers.

This cost differential has typically precluded the use of PWM rectifiers in medium performance applications.

Previous techniques typically require additional hardware or increased complexity, and sometimes involve injecting test signals or switching in loads, to estimate line impedance.

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